中文摘要：

2011年11月~2012年8月,采用WPS宽范围粒径谱仪在北京地区连续监测10nm~10μm间不同粒径大气颗粒物数浓度,并同步记录气象参数.结果表明,颗粒物数浓度均值为25014个/cm3,多呈单峰或双峰模式分布,其中冬季均值为31007个/cm3,春季23152个/cm3,夏季20882个/cm3,冬季明显高于其他季节.爱根核模态及积聚模态均呈现冬季高、春夏低的态势;核模态春季显著高于其他季节.各气象因素中,风速影响最为显著,粒径大于20nm颗粒物数浓度与风速呈反比.核模态与爱根核模态粒子数浓度在交通早高峰、正午与晚间高于其他时段,积聚模态粒子数浓度变化则相对平缓,夜间显著升高.

英文摘要：

From November,2011 to August,2012,measurements of size distribution of particle number had been conducted using WPS（Wide Particle Spectrometer,Model 1000XP） in Beijing,and main meteorological parameters such as temperature,relative humidity,wind speed and direction were collected simultaneously.The results indicated that during the monitoring period,the average total number concentration of particles between 10 nm and 10 μm was 25014 cm-3,and it was 31007 cm-3in winter,23152 cm-3 in spring,and 20882 cm-3 in summer,respectively.Most of the number size distribution exhibited in single-peak pattern or two-peak pattern.The highest particle number concentration was observed in winter.Seasonal variations in different modes also could be found.The particle number concentration and size distribution were significantly influenced by meteorological parameters,especially by wind speed.With the increase in wind speed,the Aitken mode and accumulation mode particle number concentrations decreased,while nucleation mode particle number concentrations increased.The particle number concentration of nucleation mode and Aitken mode reached the peak value at three intervals： rush hour in early morning,noon with the strongest solar radiation,and night with lower temperature inversion layer.By comparison,the particle number concentration of accumulation mode varied slightly and increased at night.